The present invention relates to an apparatus for mounting a cutting torch, such as a gas or plasma arc torch, to a shape cutting machine, and with the mounting apparatus being characterized by the ability to detect contact between the torch and an obstruction during movement of the torch by the shape cutting machine.
U.S. Pat. No. 4,415,795 to Ross et al discloses a plasma arc cutting apparatus which is designed for cutting metal plates into a desired configuration. More particularly, the patent describes a process wherein the metal plate to be cut is submerged in a water bath, and the torch is supported in a vertical orientation by a shape cutting machine, such that the lower portion of the torch is also submerged in the water bath. In operation, the shape cutting machine first adjusts the torch to the appropriate vertical working height above the metal plate, and the torch is then ignited. Next, the machine manipulates the torch horizontally to effect cutting of the plate into the desired outline. The fact that the metal plate and the output end of the plasma arc torch are submerged in a water bath, significantly reduces the noise level of the operation, and it also reduces any ultraviolet radiation which is emitted by the plasma arc.
The above referenced patent to Ross et al also discloses a mounting structure for the torch which is adapted to detect vertical contact between the torch and the workpiece, and also lateral or sideward contact with the torch, such as contact between the torch and a side wall of the water tank or other obstruction. For this purpose, a number of microswitches are provided adjacent the torch which send a signal to the shape cutting machine when such contact is detected and so that the machine will be instructed to stop movement of the torch or take other corrective action.
While the above prior system for detecting contact of the torch with obstructions is satisfactory in many respects, the presence of the electrical microswitches in the environment of the process can result in their deterioration and thus a malfunction of the process. In addition, the prior mounting structure does not always accurately return the torch to its original aligned position, particularly after the unit had been subjected to wear and tear resulting from long usage.
It is accordingly an object of the present invention to provide an apparatus for mounting a cutting torch to a shape cutting machine and which is adapted to effectively and reliably detect contact between the torch and an obstruction during movement of the torch by the shape cutting machine.
It is a more particular object of the present invention to provide a mounting apparatus for a cutting torch which is able to detect contact between the torch and an obstruction, and then signal the shape cutting apparatus to take corrective action, and without the use of electrical switches in the environment of the cutting process.
It is another object of the present invention to provide a mounting apparatus for a cutting torch which is adapted to be mechanically upset when an obstruction is encountered, and which is thereafter able to reliably return the torch to its original aligned position.